Manufacturing of semiconductor devices typically includes making a large number of semiconductor devices on a wafer. During the manufacturing process, the semiconductor devices can be separated from each other in a process called singulation. For example, the wafer can be sawed up to separate the semiconductor devices from each other. The singulated semiconductor devices can then be incorporated into other electronic devices and/or packaged.
For various reasons, fabricated semiconductor devices sometimes fail to perform correctly. Accordingly, at various points in the manufacturing process, tests of the semiconductor devices are typically performed to enable identification of defective devices. Defective devices can then be discarded, or in some cases, repaired. Types of tests performed can include functional tests, speed tests and sorting, and burn-in testing. Burn-in testing is typically performed at elevated temperatures.
Testing can be performed both before and after a wafer has been singulated into individual semiconductor devices. Typically, much of the testing has been performed after a wafer is singulated, as testing at the wafer level has presented a number of challenged. For example, burn-in testing is typically performed on semiconductor devices that have been singulated and packaged. When a semiconductor device is found to be defective after being packaged, the expense of packaging the device is therefore wasted.